Date of this Version
Southwestern Naturalist (1979) 24: 692-693.
Abronia fragrans Nutt. (Nyctaginaceae) is a white-flowered herb of dry sandy soils from Idaho and South Dakota to Arizona and Texas. It can be readily observed to fit a night-blooming, moth-pollinated syndrome (Faegri and van der Pijl, The principle of pollination ecology, 1971). This does not seem to have been noted: in all references to A. fragrans we could find, the only indication of nocturnal anthesis was the comment of Nelson (Handbook of Rocky Mountain plants, 1969), who observed that the fragrance was more noticeable at night. Tillett (Brittonia 19:299-327, 1967), working on Pacific species, suggested that the pink flowered A. umbellata was visited by moths, families Noctuidae and Sphingidae, as well as day-flying insects, but did not identify any species. We captured the moth, Nycterophaela luna (Morr.) (Noctuidae) pollinating A. fragrans in western Nebraska and confirmed the moth-pollination syndrome.
A small population of A. fragrans variously called sweet sand verbena and prairie snowball, was observed at Cedar Point Biological Station, Ogallala, Nebraska (Keith County). Observations were made in late July and early August 1977. Abronia fragans appeared near the peak of flowering for this population, since there were numerous unopened buds. However, in 1976, this and another population at Ackley Valley Ranch, Keith County, were through flowering by August 1. Plants in Keith County were observed in flower discontinuously in late May and late August 1978, apparently in response to rainfall.